Update CircleProgressBar.cs

Author: yanjinhuagood

src/WPFDevelopers.Shared/Controls/CircleProgressBar/CircleProgressBar.cs

@@ -25,7 +25,7 @@ public class CircleProgressBar : ProgressBar
 
         public static readonly DependencyProperty IsRoundProperty =
             DependencyProperty.Register("IsRound", typeof(bool), typeof(CircleProgressBar),
-                new PropertyMetadata(false));
+                new PropertyMetadata(true));
 
         public static readonly DependencyProperty AngleProperty =
             DependencyProperty.Register("Angle", typeof(double), typeof(CircleProgressBar),